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Watch Out For These Signs of Bad Universal Joint

Without a universal joint (or U-joint), you won’t be able to drive a vehicle. To make sure of the good health of your car and your safety on the road, you should be able to pick up the signs of bad universal joint.

What Is a Universal Joint?

The U-joint is a driveshaft component that is found in rear-wheel-drive trucks, four-wheel SUVs and drive trucks, and off-road vehicles.

This component transfers power from the transmission to the differential and makes up for the height misalignment between the transmission and the rear axle. Found in pairs on the driveshaft assembly, you cannot drive a vehicle without functioning U-joints.

Each end of the driveshaft is linked to a U-joint. With each rotation of the driveshaft, the joints bend to correct the misalignment. Rear-wheel-drive cars these days use constant-velocity joints instead of the U-joints for smoother driveshaft rotations.

Signs of Bad Universal Joint: Cues to Look for.

There will be some symptoms of failing universal joints. Picking up these warning signs of a bad U joint is likely to save your car from being towed to a repair shop.

Squeaking noises.

Does your car squeak when it starts moving after kicking off the engine? It becomes noticeable when the car moves forward or goes into reverse but goes away when the vehicle speeds up to over 5 to 10 mph.

signs of a bad u joint
Greasing the joints is enough to solve this issue. (Photo Source: autoyas)

Why does this happen? The universal joints have bearing components that are greased at the factory. Now, this greasing can be used up or evaporated over time. Each rotation of the driveshaft makes the bearings twist a little. So, dry bearings cause metal-to-metal contact, and excessive friction leads to squeaking noises and corrosion.

The screeches are a reminder to have a professional mechanic diagnosing and servicing the universal joints. Timely servicing will extend the lifespan of the joints and save the driveshaft from breaking down.

A clunking sound.

Clunks are signs of bad universal joint, especially when you hear them when shifting the vehicle from ‘Drive’ to ‘Reverse’.

The clunking sound means the bearings allow the driveshaft to rotate a little before stopping hard when the power is reversed. This can simply be the next stage of producing squeaks due to insufficient grease amount in the bearings. Some damage has already been done at this stage that you cannot undo but servicing will definitely slow the ruination down.

Vibrations while speeding up.

The next phase of clunky bearings is a strong vibration felt throughout when you accelerate the vehicle. This results from the imbalanced movement of the driveshaft.

When the grease dries up and the bearings are worn enough to not be able to control the driveshaft’s movement. Its deviation from its regular rotational route causes that vibration.

Are you familiar with the vibrations caused by imbalanced wheels? The frequency of this vibration will be more intense because a driveshaft rotates at least three times quicker than the wheels.

This symptom means that the U-joints have started affecting other components, including the transmission. A diagnosis and repair job is necessary at this period if you want to prevent further damage.


Transmission fluid leaking.

This fluid leaks for many reasons and bad U-joints are one of them. You can be sure about it when the leakage occurs in the rear of the transmission.

If you ignore the vibrations, unstable driveshaft rotations are likely to wear out the transmission tailshaft bushing and output shaft seal, causing the leaking of the fluid.

When this happens, thoroughly examine the transmission to find out the source of the leak and take repair actions.

The car does not move.

This is the last step of U-joints failure. You may have already seen a vehicle stationed on the side of a road with its driveshaft lying underneath. It means that the driveshaft literally breaks down and disjoints from the rear axle or transmission. Repairing at this point may require the replacement of the driveshaft and even more.

how long can you drive with a bad u joint
Don’t wait till the car breaks down. (Photo Source: diesel-gate)

How Long Can You Drive with a Bad U Joint?

When the U-joints completely fail, you are left with no other option than towing the car to a mechanic. To avoid this, you should pick up the signs of bad universal joint discussed above.

Normally, the U-joints last the lifetime of a vehicle. But anything in your car can break down anytime, so the joints may also need replacement.

If they are not running properly, you will need to replace them as soon as possible. Also, remember to replace them in pairs to avoid more troubles in the future. If you need to drive for a while with bad U-joints, do it without running on 4WD. Using 4WD can make the shafts explode or rip apart.

The safest option for you and the vehicle is to seek professional help when you start noticing the symptoms of failing U-joints.

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